Dear Val,
Keep telling yourself - it's only one person, it's only one person, it's only
one person.  The person who criticized you is known to be difficult by the
people who asked you to speak, and by all of her co-workers.  People like
that are frustrating and you are very lucky she left early.

It's really hard to be thrown off your stride like that.  When it happens,
it's hard to get it back again.  Please don't allow this incident to drain
away any more of your precious energy.  You are a good speaker - they asked
you back twice.

Perhaps we could post a few "I should have said...." comments to help us all
deal with the difficult participant in the future.

Here's mine:
Since you seem to know this information so well, why don't I sit down in your
place and you can deliver the rest of my lecture.  I'm as tired of hearing
the sound of my own voice as you seem to be.

Obviously, that's something I WISH I could say on occassion :-D

Jeanne Fisher
Austin, TX